Hi to all! thanks to your precious advices now I'm able to build a graphic driver for a vivante gpu (Nitrogen6X board). I placed the driver under /usr/lib/xorg/modules/drivers/, placed the correct xorg.conf file and booted the system. The screen is on (so the video signal is detected) but remains black. The Xorg.0.log seems ok (http://pastebin.com/PVqLtEJR) (I'm trying to boot only in 2D because 3D seems a problem on vivante gpu).